Budget Breakdown: Here’s What it Cost to Build Two ADUs on the Same Bay Area Block

In 2019, Susan and Chuck Webb relocated from Bowling Green, Kentucky, to Berkeley, California, to be closer to their daughter and grandson. The retired couple soon realized they’d need more space than their century-old, 1,300-square-foot craftsman bungalow could provide in order to spread out, host out-of-town visitors and, perhaps eventually, accommodate a live-in caretaker.

Around the corner, a young professional couple likewise needed more space than their own similar-sized craftsman offered. Anticipating having children of their own, Julie and Joe wanted to be able to provide seasonal lodging for Julie’s retired parents, who live most of the year in in Hawaii.

Both couples decided to supplement their homes with backyard ADUs designed and built, incidentally, by the same local company: Type Five. The new structures are situated within 100 feet of each other—and although they vary in design, cost, and square footage, they both signify the growing embrace of ADUs as practicable multifamily housing solutions.

Susan and Chuck’s Studio

Back in Bowling Green, where housing costs 28 percent less than the national average, Susan and Chuck were used to living in a home twice the size of their new digs; and with Berkeley’s median home sale price at around $1.4 million, the new neighborhood was a big change, too.

"Almost every house on the block has two bedrooms and one bath," says Susan, a retired art teacher. "And there are lots of shared units to help cover costs and meet the need for housing."